Manufacture of paper-makers&#39; wire cloth



Jan. 10, 1939. w. D. T. GREEN MANUFACTURE OF PAPER MAKERS WIRE CLOTH Filed Sept. 7, '19-'57 \Jzz/z/e 'Zlie Z5028 ianjeafar I item (2 7 Fig. I.

20201". e Green Patented Jan.- 10, 1939 land, assignor to The United WireWorks, Limited, Granton, Edinburgh, Scotland r 1, 1931, Serial mamas-n ritain April ca, 1937 Application 'Septe In Great PATENT OFFICE t r slsum Esteem 3 Claims. (Cl. 245-8) This invention has for its object the production of an improved paper makers woven wire cloth of the kind woven with a long crimp, such as a twill weave or multiple weave or any other combination of a twill weave; that is to say, in which round weft wires pass alternately under one round warp wire and over two or more round warp wires, the intersection of weft with warp being advanced by one or more warp wires at 10 each successive pick.

Until recent years, twill weave paper makers wire cloth has exhibited a weft, the crests'of the long crimps of which lie considerably below the level of the crests of the warp knuckles and thus do not provide an adequate paper support.

In order to provide a more adequate paper support, the crests of the long crimps of the weft should be raised as nearly as possible to the level of the crests of the warp knuckles. It is also generally desirable that the weft wires should be equal to or of greater diameter than the warp wires because any reduction of the diameter'of the weft wire decreases its ability to control and crimp the warp wires and may result in a flimsy -35 cloth. However it is my experience that when attempts are made to obtain both these desiderata, the long weft crimps become sloped, due

, to the control exercised by the warp wires, with the result that instead of the web of paper being 30 supported on the warp knuckles and the whole of the long weft crimps, it is supported either on the warp knuckles alone, or on the warp knuckles and the highest ends only of the long weft crimps.

The present invention provides an improved 3.; twill weave or long crimp paper-makers wire cloth giving adequate paper support without necessarily decreasing the diameter of the weft wire and without departing from the use of round (i. e. circular section) wire for the warp or for 40 both warp and weft, at the same time obtaining ample drainage characteristics.

The present invention is concerned with a twill weave or multiple weave paper maker wire cloth in which the warp is of circular cross ection and 45 in which the crests of the longweft crimps are raised as nearly as possible to the level of the crests of the warp knuckles, that is to say, the crests of the long crimps .of the weft are in a plane which lies at a distance less than half the 50 diameter of the warp wire below the plane of the crests of the warp knuckles. According to the present invention, such a twill weave or multiple weave wire cloth in which the weft wire is preferabLv equal to or of greater diameter than the 55 warp wire, is subjected to a surface grinding operation restricted to grinding down only the outer or raised warp knuckles until the flat surfaces thus formed thereon are level with the crests of the long weft crimps.

In a desirable form of the invention the rela- ,5 tive proportions of weft and warp are such that the crests of the long weft crimps are raised to or slightly above the level or plane of the crests of the outer or-raised warp knuckles, and the aforesaid restricted grinding operation is carried to 10 such an extent asto grind off the crests of the sloping long weft crimps, thus forming a flat surface on each long weft crimp. The flat surfaces formed by down the warp knuckles not only in themselves provide additional paper 15 support, but also reduce to nothing the distance between the crests of the long weft crimps and the paper, so that if the diameter of the weft or the number of beats of weft per inch is such that the level of the crests of the long weft crimps 20 is below the level at which the restricted grinding down of the warp knuckles will alsosimultaneously grind off the crests of the long weft crimps, the grinding down of the,warp knuckles to the level of the crests of the long weft crimps will nevertheless enable the sloping long weft crimps to support the paper.

If the grinding operation is carried to such an extent as to grind of! the crests of the sloping weft crimps, the improved wire cloth provides a paper supporting surface characterized by a series of oval or pear-shaped flat spots on both warp and weft and these afford improved paper support without impairing the drainage efliciency of the cloth. Furthermore, this can be attained without diminishing the diameter of the weft wires.

In order that the invention may be more clearly understood, the accompanying sheet of drawings .will be hereinafter referred to; these. drawings paper makers wire cloth and Fig. 2'is a sectional view through one of the weft wires on line 2-2 of Fig. 1. i

Figs. 3 and 4 are views corresponding to Figs. 1

and 2 illustrating the same wire cloth when flnished according to the invention.

Figs. 5' and 6 are views corresponding to Figs. 1

and 2, but showing a more closely woven 80 mesh twill weave paper makers wire cloth before being finished according to the invention, and Figs. '1

times actual size.

The wire cloth shown in Figs. 1 and 2 was made from 0.0096 inch diameter round bronze warp wire and 0.0104 inch diameter round brass weft wire with 60 warp wires per inch and 44 weft wires per inch.

Throughout the drawing the weft wires are designated by the reference characters a, b and c and the warp wires by the characters d, e and f, this system of references being adopted because every fourth wire is a repeat of the first wire. It will also be seen that the weft wires (1 pass under warp wires d and over warp wires e and j, that the weft wires b pass under warp wires e and over warp wires f and d, and that the weft wires '0 pass under warp wires f and over warp wires d and e. I

Referring now to Fig. 2, what is termed the long crimp of the weft wire is the portion which passes over two warp wires and the crest of this long weft crimp is substantially below the plane of the crests of the raised warp knuckles of the wires (1, that is to say, where the warp wires d pass over the weft wire a. The crests of the long crimps of the weft wires b and c are similarly substantiallybelow the plane of the crests of the raised warp knuckles of the warp wires d, e and f. This is due partly to the diameter of the weft Wire exceeding the diameter of the warp wire and partly to the number of beats of weft wire per inch (viz. 44 per inch). It will be obvious that the paper pulp will be supported mainly by the raised knuckles of the warp wires d, e and f and that the paper pulp will sink in the spaces between the warp knuckles until it rests on the long weft crimps; it will be seen furthermore from Fig. 2 that the warp wire I is slightly lower than the warp wire e where the weft wire a passes over them, with theresult that the long weft crimp slopes slightly downwards as it passes over the warp wire f. The same result occurs throughout the fabric wherever a weft wire passes over the warp wires; this sloping of the long weft crimps is caused by the control of the warp wires upon the weft wires. The control of the warp wires over the weft wires and the consequent sloping of the long weft crimps is accentuated if the diameter of the weft wire is reduced or the number of beats of weft per inch is increased. Either or both of these measures will, however, raise the level of the long weft crimps. The effect of adopting both these measures together is shown in Figs. 5 and 6 which show a twill weave wire cloth woven with 60 warp wires per inch and 55 weft wires per inch, using 0.0096 inch diameter bronze warp wire and 0.0096 inch brass weft wire. It will be observed that this raises the crests of the long weft crimps approximately to or slightly above the plane of the crests of the raised warp knuckles, but further depresses the warp wire I in relation to the warp wire e where the weft wire a crosses them and thus accentuate the slope of the long weft crimps throughou the cloth. The cloth shown in Figs. 5 and 6-provides a better paper support than the cloth shown in Figs. 1 and 2, but the paper pulp is supported only by the relatively small supporting surfaces afforded by the crests of the raised warp crimps and the sloping weft crimps.

Figs. 3 and 4 illustrate the cloth shown in Figs.

1 and 2 when finished according to the invention by grinding off the crests of the raised warp knuckles to provide fiat surfaces 9. It will be apparent that the fiat surfaces 9 increase the area -of the supporting surface for the paper pulp. The crests of the raised warp knuckles are ground down until level with the crests of the long weft crimps, so that the paper pulp will be suppo d not only by the fiat surfaces 9 of the w knuckles but also by the crests of the long weft crimps.

Figs. 7 and 8 illustrate the cloth shown in Figs.

5 and 6 when finished according to the invention,

wherefrom it will beseen that the grinding down of the crests of the raised warp knuckles to produce the flat warp knuckle surfaces 9 also grinds oil the crests of the sloping long weft crimps and provides fiat spots 72. on the long weft crimps, so that the paper pulp will be supported not only by the flat surfaces 9 of the raised warp knuckles, but also by the fiat surfaces h on the long weft crimps".

- It is to be understood that the invention is not limited to the regular twill weave illustrated in the drawing; the invention can be applied to irregular twill weaves, such as combinations of a twill weave, or multiple weaves in which each weft wire passes over more warp wires than it passes under and in which adjacent weft wires pass under difierent warp wires. The invention is also not limited to a 60 mesh weave; it may be applied to any regular or irregular twill weave employing round warp and round weft wires, although its chief application will probably be to the meshes of wire cloth within the range of 40 to 80 mesh.

Although it is preferred to use circular section wire for both warp and weft, it will be obvious that circular section warp wires might be interwoven with weft wires of elliptical, square, oblong or other non-circular cross-section, the relative cross-sectional areas of the warp and weft wires and the ratio of the number of warp wires per or is slightly above the plane of the crests of the outer or raised warp knuckles as in Fig. 6, or which lies at a distance less than half the diameter of the warp wire below the plane of the crests of the warp knuckles. If square or oblong section weft wire is employed, its corners will be preferably rounded off in a wire-drawing die before weaving. It has been previously proposed to inter-weave circular section warp wire with weft wire of fiat, elliptical or oval cross-section in making paper makers wire cloth and I do not claim the use of weft wire of non-circular section tobe a feature of my invention.

I claim: 0

1. The method of manufacturing paper makers wire cloth which comprises the following steps: Y

selection of round warp wire of suitable size and material, selection of round weft wire of suitable material and of a diameter not less than the diameter of the warp wire, interweaving the warp and weft wires so that each warp wire passes over one and under two weft wires thereby forming warp knuckles and long sloping weft crimps, the warp and weft wires being interwoven in such ratio that the long weft crimps have crests in substantially the same plane as the crests of the raised warp knuckles, and removing material from the raised projecting warp knuckles to bring them into the same plane with the crests of the long weft crimps and thereby produce a wire cloth affording ample drainage with increased paper support.

2. A paper makers wire cloth consisting of warp and weft wires, each warp wire passing over one and under two or more weft wires and each warp wire being of a circular cross-section substantially equal in area to the circular cross-sectional area of the weft wire, the warp wires forming knuckles where they pass over the weft wires and the weft wires forming sloping raised crimps where they pass over two warp wires, the warp knuckles having flat tops formed by removal of material therefrom, the crests of the raised crimps in the weft wires being in a plane with the flat surfaces on the raised warp knuckles, and each raised warp knuckle in vertical section through the middle of the crest having the shape of the major segment of a circle.

3. The method of manufacturing an improved paper makers wire cloth which comprises weaving a twill wire cloth of warp and weft wires of circular cross-section so that the warp wires form raised warp knuckles and the weft wires form down only the crests of the raised warp knuckles until the fiat surfaces thus formed are level with the crests of the long weft, crimps.

WILLIE DUNSTAN THEODORE GREEN. 

